The present invention relates to an electronic control unit.
A control unit is described in German Published Patent Application No. 198 51 455 and is used, for example, for controlling an electromotively operated drive unit. The known control unit includes a box-shaped, plastic base part provided with two connector parts, the printed circuit board being inserted into the base part, which can be closed with a cover. The box-shaped base part is produced together with the connector parts as injection-molded parts.
In the case of the known control unit, it is disadvantageous that it is problematic to introduce power components into the housing since there is no heat sink, and the heat from the closed plastic housing cannot be released to the surroundings. In addition, introducing a heat sink into the housing is quite complicated and would result in a disadvantageous enlargement of the housing. Both an optimum dissipation of heat and a simple, mechanical design are not possible in the case of the known control unit.
Using the control unit according to the present invention. The disadvantages known in the related art are prevented. The control unit is inexpensive to manufacture using a minimum of components and has an exceedingly compact design. Particularly advantageous is the very flat, space-saving construction having a minimal overall height in combination with the realization of an efficient dissipation of the heat generated by the power components. This is advantageously achieved in that the housing is formed by a housing frame that is open on both sides, and whose open bottom side is covered by a metallic heat sink that forms the base part of the housing, the power components situated in the housing being in contact, on their sides that face away from the printed circuit board and that are provided as a cooling surface, with the heat sink. Contact elements of the connector parts and peak current-carrying conductor strips are formed in a simple manner by a punched grid, which can be embedded in the housing frame by injection molding. The leads of the power components can advantageously be contacted by the printed circuit trace of the printed circuit board and/or by sections of the punched grid not embedded in plastic.
It is advantageous that the housing frame is provided with crossbars on which a holding arrangement for the power components and/or a holding arrangement for further electrical components are formed. As a result, not all components must be positioned on the printed circuit board, and large components, which use a lot of space, can be fastened to the holding arrangement of the housing frame, independently of the printed circuit board. Due to this measure, the overall height of the arrangement is significantly reduced. Moreover, as a result of the crossbars, a particularly stable construction as well as a simpler assembly are achieved. Thus, large capacitors, for example, can be preassembled on the housing frame, and the printed circuit board can be subsequently fixed to the housing frame.
Advantageously, the contact elements of the at least one connector part are formed by the metallic conductor strips of the punched grid.
Furthermore, it is advantageous to arrange the printed circuit board between the conductor strips and the cover part. As a result, the leads of the power components, which are situated on the side of the printed circuit board facing the metallic base part, are electrically connected to the printed circuit board and/or to the conductor strips of the punched grid. Therefore, it is possible, for example, for high current-carrying leads of power transistors to directly contact the conductor strips and for signal-current-carrying lead to be directly connected to the printed circuit board.
As a result of the contact segments of the conductor strips bent in the direction of the topside of the housing frame passing through contact openings of the printed circuit board and being electrically connected to the printed circuit board, the electrical connection between the punched grid and the printed circuit board can be produced in a simple manner, e.g. by dip-soldering.
Advantageously, the topside and/or the bottom side of the housing frame is/are provided with a circumferential seal on which the cover part and the base part are placed. A particularly effective protection against moisture and environmental influences can be achieved by the housing formed from the housing frame, metallic base part, and cover part being a hermetically sealed housing.
The compact, flat construction can be further improved by the metallic base part being provided with at least one retraction space and/or at least one platform for supporting the power components and/or the additional electrical components.